Typically, a semiconductor device is implemented on a wafer by repeating wafer processes such as an oxidation process, a diffusion process, an etching process, and a metallization process, and then slicing and packaging processes are performed to make a shipment. In addition, the semiconductor device implemented on the wafer is subject to a probing test for verifying whether it is acceptable or not after completing the wafer processes but before slicing them.
In such a probing test, predetermined electrical signals are applied from a test equipment through probe tips of a probe card coupled with electrode pads in the chips on the wafer and then the corresponding output electrical signals are received to test whether the chips on the wafer are acceptable or not.
Also, in such a probing test for testing whether chips on the wafer are acceptable or not, it is typical to use a probe card which comprises probe tips corresponding to the lay-out of the probed (i.e., each of pads implemented on a semiconductor substrate).
As seen in Korean Patent Application No. 2001-0074710, in a conventional probe card assembly 500, a probe pin or a contact element 524 makes contact with the bonding pads 526 on the semiconductor wafer 508.
The probe card assembly includes several elements which are assembled together, including a probe card 502, an interposer 504, and a space transformer 506. The probe card 502 is typically a printed circuit board, which includes circuit traces to various electrical components, which are used in performing the electrical tests of the semiconductor die being probed.
Contact elements on the probe card 502 make contact with the bonding pads 526 through a series of intervening layers including the interposer 504 and the space transformer 506.
The interposer 504 provides for a resilient or spring-like positioning in the vertical or z direction in order to provide adequate contact for all contact elements at the bonding pads regardless of the length of the contact elements used on the intervening layers, such as the contact elements 524 which resemble springs. The space transformer 506 performs a pitch reduction and is also the substrate on which resilient contact elements are disposed.
In more detail, the interposer assembly 300 has a substrate 302 on which resilient contact elements are attached, including contact elements 312, 314, 316, and 318. Contact elements 312 and 316 are electrically coupled from one side of interposer 300 to the other side by a through connect 304A, and contact elements 314 and 318 are electrically coupled by a through connect 306A.
Accordingly, contact elements such as springs in the interposer 504 assembly 300 are attached to the substrate 302 by a wire boding process or the like. Therefore, a process of fabricating the assembly is very difficult and causes a lot of processing time losses.
Particularly, the wire bonding process for the resilient contact elements such as springs is performed two times for both top and bottom surfaces of the substrate 302. This makes the process more difficult and causes more processing time losses.
Along with the above problems, since the resilient contact elements such as springs are attached to both top and bottom surfaces of the substrate 302 by the wire bonding process or the like, the attached portions can be easily deteriorated. In addition, since the resilient contact elements such as springs are attached to both top and bottom surfaces of the substrate, the total path length of the electrical signal increases so that electrical noises can easily occur.
In addition, since the probe card assembly comprises an element, the interposer which includes the substrate, the total cost of manufacturing the probe card assembly increases.